Microvalve

Abstract

A microvalve with a multi-layer structure for regulating or controlling fluid flows is proposed. In a first layer at least one feed connector, a first return connector, at least two working connectors and at least a second return connector are structured. The microvalve has a second layer which is connected via an at least first structured intermediate layer with the first layer. Means are structured in the second layer which are electrostatically operable and by means of which the degree of opening of the at least one feed connector can be changed. The microvalve is constructed symmetrically in respect to the second layer, in that a third layer, structured mirror-reversed in respect to the first layer, is applied to the second layer via a further structured intermediate layer. Thus the third layer has at least two further working connectors, at least one further feed connector and at least two further return connectors, where each two of the connectors located opposite each other in the first layer and the third layer form a pair. At least one flat slider with at least two flow-through openings is structured in the second layer to form an electrostatically operable means.

We claim: 
     
       1. A microvalve with a multi-layer structure for regulating or controlling fluid flows with a first layer, in which at least one feed connector and at least a first return connector is structured, and with a second layer which is connected via an at least first structured intermediate layer with the first layer, where means are structured in the second layer which are electrostatically operable, because of which the degree of opening of the at least one feed connector can be changed, characterized in that at least two working connectors (A, B) and at least a second return connector (T2) are structured in the first layer (1),   the microvalve is formed symmetrically in respect to the second layer (2), in that a third layer (3), structured mirror-reversed in respect to the first layer (1), is applied to the second layer (2) via a further structured intermediate layer (5), having at least two further working connectors (A', B') and at least a further feed connector (P'), where each of two connectors located opposite each other in the first layer (1) and the second layer (2) form a pair, and   at least one flat slider (20), displaceable in the layer level and having at least two flow-through openings (24, 25) is structured in the second layer (2) as an electrostatically operable means.   
     
     
       2. A microvalve in accordance with claim 1, characterized in that the working connectors (A, A', B, B'), the feed connectors (P, P') and the return connectors (T, T') are formed as flow-through openings in at least one of the first layer (1) and the third layer (3).   
     
     
       3. A microvalve in accordance with claim 1, characterized in that the working connectors (A, A', B, B'), the feed connectors (P,P') and the return connectors (T,T') are formed as tubular channels, parallel to surfaces of said layers, in said first and third layers, and are formed with connecting openings (10) to said second layer only adjacent flow-through openings (24, 25) of said flat slider (20).   
     
     
       4. A microvalve in accordance with claim 1, characterized in that the flat slider (20) is connected with the second layer (2) at at least one transverse beam (22).   
     
     
       5. A microvalve in accordance with claim 4, characterized in that the first structured intermediate layer (4) and the second structured intermediate layer (5) have recesses in the areas of the flat slider (20) and the transverse beams (22).   
     
     
       6. A microvalve in accordance with claim 1, characterized in that the second layer (2) is reduced in thickness in the areas of the flat slider (20); and   the transverse beams (22), the first layer (1), and the third layer (3) are reduced in thickness on the surfaces facing the second layer (2) in the areas of the flat slider (20) and the transverse beams (22).   
     
     
       7. A microvalve in accordance with claim 1, characterized in that in a first position of the flat slide (20) the at least two flow-through openings (24, 25) each provide a connection between the working connectors (A, A', B, B') forming a pair, without there being a connection of the working connectors (A, A', B, B') with the feed connectors (P, P') or the return connectors (T1, T1', T2, T2'), and in at least two further positions of the flat slider (20) the at least two flow-through openings (24, 25) provide a connection between a pair of working connectors (A, A'; B, B') and the at least one pair of feed connectors (P, P') and a connection between another pair of working connectors (B, B'; A, A') and a pair of return connectors (T1, T1'; T2, T2').   
     
     
       8. A microvalve in accordance with claim 1, characterized in that the first position of the flat slider (20) is the rest position of the microvalve.   
     
     
       9. A microvalve in accordance with claim 1, characterized in that at least one electrode (571, 572) is disposed on each one of the top and underside of the flat slider (20) and of the transverse beams (22),   on the surfaces of the first layer (1) and the third layer (3), facing the second layer (2), counter-electrodes (581, 582, 591, 592) are disposed, offset in the displacement direction with respect to the electrodes (571, 572) applied to the flat slider (20), and   there are means for applying a voltage, between the electrodes (571, 572) on the flat slider (20) and the counter-electrodes (581, 582, 591, 592), on the first layer (1) and the third layer (3).   
     
     
       10. A microvalve in accordance with claim 9, characterized in that the electrodes (572) on the top of the flat slider (20) are disposed symmetrically in relation to the electrodes (573) on the underside of the flat slider (20), and that   the counter-electrodes (58, 581, 582) on the first layer (1) are disposed symmetrically in relation to the counter-electrodes (59, 591, 592) on the third layer (3).   
     
     
       11. A microvalve in accordance with claim 9, characterized in that the electrodes (571, 572) and the counter-electrodes (581, 582, 591, 592) are realized as thin metallic layers.   
     
     
       12. A microvalve in accordance with claim 1, characterized in that the structures of the layers (1, 2, 3) of the microvalve construction are transferred by the lithographic structure transfer method in the batch process to a suitable layer material, preferably silicon or glass, and   the layers are bonded to each other.   
     
     
       13. A microvalve in accordance with claim 9, characterized in that the electrodes (571, 572) and the counter-electrodes (581, 582, 591, 592) are realized as doped silicon layers.